Page 384 - My FlipBook

240 PATHOLOGY OF THE HARD TISSUES OF THE TEETH.
surgery, etc. In the absorption of the roots of the teeth, or any
of these substances, the whole of the tissue is removed complete
without a perceptible softening in advance. The whole process
is something entirely different from what we know as decalcifi-
cation.
Absorption of the root of the central incisor begins, practi-
cally, when the child is four years old and is ended at seven. The
lateral incisor begins to be absorbed at five years and is ended at
eight. The absorption of the root of the first deciduous molar
is begun at seven and completed at ten years. The second molar
has begun to be absorbed at eight and is completed at eleven.
The absorption of the cuspid root begins at about nine years
and is completed at twelve. In the formulation of this state-
ment, it has been the endeavor to put it in a form that will be
easily remembered. (1) In the absorption of the roots of the
deciduous teeth the incisors begin, the central at four, the lateral,
five; (2) skip a tooth and a number and the molars begin to be
absorbed, the first at seven, the second at eight; (3) skip back
to the cuspid which begins to be absorbed at nine years.
There is a difference in time in the absorption of roots of
teeth between different individuals. Some will be a year or so
early or as much late. Also, the time between the individual
teeth of the person may be considerable. Perhaps this four and
five years for the central and lateral is not quite the average;
four and four and a half would be more nearly the average ; but
this is a figure that is easily remembered and is placed in that
way, as being the closest proximation in whole numbers. Occa-
sionally the lateral incisors fall away before the centrals, but
that is rare. Often they fall away about the same time, or very
close together ; not six months between. Often again, there will
be two years between. With the molars it is the same way.
Often the second bicuspid will be in place before the first bicus-
pid, the molars having fallen away in this order. All of these
differences may be found. It does not run absolutely as repre-
sented in the illustration, but this represents a fair approxima-
tion to the average.
When the absorption of the root of a tooth has proceeded
some little distance, it would be improper to place arsenic in that
tooth for the purpose of destroying the pulp. While the root is
complete, arsenic may be used for destroying pulps in the decidu-
ous just the same as in the permanent teeth, but one must have
a care as to the time at which arsenic is used. Furthermore, if
the root of a tooth is absorbed half way, a root filling could not